BIO 111 Study Part 2

Which drawing in the figure depicts the electron configuration of an atom that can form covalent bonds with two hydrogen atoms? A B C D E

C

What results from an unequal sharing of electrons between atoms? a) a polar covalent bond b) a nonpolar covalent bond c) an ionic bond d) a hydrophobic interaction

a) a polar covalent bond

Based on your knowledge of the polarity of water molecules, the solute molecule depicted in the figure is most likely a) positively charged. b) hydrophobic. c) without charge. d) negatively charged. e) nonpolar.

a) positively charged.

Water molecules have a polarity, which allows them to be electrically attracted to other water molecules and other polar molecules by weak chemical bonds known as _____. a) ionic bonds b) hydrogen bonds c) Van der Waals interactions d) polar covalent bonds e) nonpolar covalent bonds

b) hydrogen bonds

A covalent bond is likely to be polar when a) the two atoms sharing electrons are different elements. b) one of the atoms sharing electrons is much more electronegative than the other atom. c) oxygen is one of the two atoms sharing electrons. d) the two atoms sharing electrons are the same element. e) the two atoms sharing electrons are equally electronegative.

b) one of the atoms sharing electrons is much more electronegative than the other atom.

Which of the following are the strongest molecular interactions? a) van der Waals interactions b) ionic bonds in an aqueous environment c) covalent bonds d) hydrogen bonds e) van der Waals interactions in a nonpolar environment Submit

c) covalent bonds

The four main categories of large biological molecules present in living systems are __________. a) nucleic acids, carbohydrates, monosaccharides, and proteins b) proteins, DNA, RNA, and steroids c) proteins, nucleic acids, polysaccharides, and lipids d) RNA, DNA, proteins, and carbohydrates e) monosaccharides, lipids, polysaccharides, and proteins

c) proteins, nucleic acids, polysaccharides, and lipids

Which of the following subatomic particles always has a positive charge? a) element b) neutron c) proton d) electron e) atom

c) proton

A substance that cannot be broken down into other substances by ordinary chemical procedures is a(n) _____. a) molecule b) isotope c) proton d) element e) compound

d) element

The type of bonding and the numbers of covalent bonds an atom can form with other atoms are determined by __________. a) the number of protons b) the number of neutrons c) the size of the atom; smaller atoms are chemically more reactive d) the number of unpaired electrons in the valence shell e) the nucleus

d) the number of unpaired electrons in the valence shell

A pH of 6 is how many times more acidic than a pH of 9? a) 3 b) 30 c) 100 d) 300 e) 1,000

e) 1,000

About 20-25% of the 92 natural elements are known to be essential to life. Which four of these elements make up approximately 96% of living matter? a) carbon, sodium, hydrogen, nitrogen b) oxygen, hydrogen, calcium, nitrogen c) carbon, oxygen, phosphorus, hydrogen d) carbon, oxygen, nitrogen, calcium e) carbon, hydrogen, nitrogen, oxygen

e) carbon, hydrogen, nitrogen, oxygen

A covalent chemical bond is one in which a) protons and neutrons are shared by two atoms so as to satisfy the requirements of both atoms. b) outer-shell electrons of one atom are transferred to fill the inner electron shell of another atom. c) an electron from a full outer electron shell of one atom is shared so as to occupy the outer electron shell of both atoms. d) electrons are removed from one atom and transferred to another atom so that the two atoms become oppositely charged. e) outer-shell electrons of two atoms are shared so as to occupy the outer electron shells of both atoms.

e) outer-shell electrons of two atoms are shared so as to occupy the outer electron shells of both atoms.

Hydrogen bonding is most often seen _____. a) when the bonds within the molecule are nonpolar covalent bonds b) if the molecule consists of three or fewer atoms c) when multiple carbon atoms are present d) in molecules whose three-dimensional shape is tetrahedral e) when hydrogen is covalently bonded to an electronegative atom

e) when hydrogen is covalently bonded to an electronegative atom